A man named Gordon Cushing, whose wife disappeared in 2010, receives two severed human ears along with a ransom note. The ear DNA matches that of Cushing’s wife, Sarah. At the ransom exchange, Cushing pursues the suspect and accidentally kills him. Clues on the suspects body lead Joan and Sherlock to an AA meeting, where they find Sarah, who is both alive and not earless. Sarah says that the DNA they collected when she disappeared was not hers and belongs to her husband’s mistress, who, as it turns out, died in 2011. Sherlock realizes that Sarah’s new plastic surgeon husband grew two exact replicas of her ears on Sarah’s back, and then cut them off in an elaborate attempt to collect ransom from Cushing. Meanwhile, Lestrade is mugged and Joan encourages him to solve his own case to improve his spirits.